This invention relates generally to electrophotographic printers and copiers, and more particularly, concerns removing paper fibers and dust from copier paper.
Paper transport mechanisms in photocopiers usually employ several pairs of rollers. The paper sheet is handed from roller to roller as it moves through the photocopier. Although this method works well for transporting paper, the contact between the rollers and the paper sheet causes abrasion of the paper sheet. The paper sheet abrasion creates dust and paper fibers that contaminate the xerographic engine and causes copyquality problems. An objective of the present invention is to remove the paper dust and fibers from the paper sheet before it enters the transfer zone of the xerographic engine.
The following disclosures may be relevant to various aspects of the present invention and may be briefly summarized as follows:
U.S. Pat. No. 3,970,905 to Itoh et al. discloses an electric field curtain system for use in transportation, repulsion, confinement, and brushing away of powder particles. The electric field curtain system includes a plurality of thin linear electrodes embedded in an insulator layer in parallel to each other so that curved electric lines of force which are outwardly convex are produced on the surface of the insulator layer.
U.S. Pat. No. 3,981,498 to Fletcher discloses a paper sheet transport wherein a non-uniform charge is applied to a surface of a sheet material and/or a surface of a conveying belt so that higher electrostatic forces between the sheet material and the conveying belt are obtained. The nonuniform charge pattern is applied using a textured roller.
U.S. Pat. No. 4,864,461 to Kasahara discloses a machine unit having an electrostatic retention means comprising a conveying belt (or roller), a pair of electrodes and a power source circuit for supplying positive and negative charges to the pair of electrodes while changing the polarity thereof. The power source circuit includes a DC power source having first and second terminals and switching means connected between the terminals and the pair of electrodes for alternately reversing the electrical polarity of the electrodes.
U.S. Pat. No. 5,003,325 to Bibl discloses an electric field paper stabilizing system including a continuous transport belt having a conductive surface conformably coated with a minimally thin dielectric material of high dielectric strength and permitivity. A recording medium such as electrostatic writing paper has a conductive surface adjacent the dielectric coating on the conductive transport belt. Electrodes are provided in the dielectric coating for holding the paper at ground potential. A differential potential is applied between the back side of the paper and the conductive transport whereby the paper and belt function as parallel conductive plates of a capacitor. The electric field developed between the conductive paper and the belt provides a strong hold down force which immovably registers the paper to the belt.
U.S. Pat. No. 5,008,968 to Preston discloses a sheet material cleaning machine comprising a conveyor for moving a sheet of material to be cleaned along a predetermined path through first and second cleaning stations. At the first cleaning station, portions of the surfaces of the sheet exposed by the conveyor are cleaned by passing the sheet between ionization bars which neutralize static electrical charges on the sheet. Subsequently, the sheet is conveyed between air jets and rotary brushes to clean the exposed surfaces of the sheet. Portions of the sheet not exposed at the first cleaning station are exposed at the second cleaning station where a similar cleaning process is repeated. As the sheet leaves the cleaning machine, it passes another ionization bar which neutralizes static charges produced by frictional engagement of the air jets and rotary brushes with the sheet surfaces.